The invention refers to a facility for needling of fleece with at least one needle board driven to and fro in stitching direction, which can be additionally driven in pendulum fashion in fleece feed direction via an eccentric drive provided with a connecting rod articulated at a rocker arm and a connecting pitman to the needle board effective on this connecting rod assembly.
To permit the fleece to be advanced also during engagement of the needles, it is known (DE 196 15 697 A1) to provide an additional needle board drive moving to and fro in fleece feed direction, so that the fleece feed is extended by the motion component of the needle board in fleece feed direction. Like the main drive effective in needle stitching direction, this additional drive for the needle board is realized via an eccentric drive, the connecting rods of which are articulated to the needle bar carrying the needle board. To adjust the rocking amplitude of this additional eccentric drive for the needle board effective in fleece feed direction, it is further known (EP 0 892 102 A2) to adjustably link the connecting rod of this additional eccentric drive to a rocker arm in such a way that the rocking amplitude of the rocker arm is changed upon displacement of the link. Therefore, via a pitman effective between this rocker arm and the needle board, the needle board can be driven in fleece feed direction at various rocking amplitudes. However, the disadvantage of this known construction is that a displacement of the connecting rod link at a rocker arm during driving of the needle board can be effected only by way of a very complex construction, so that, because of the usual demand for adjustability of the motion component of the needle board in fleece feed direction during driving of the needle board, an eccentric drive with such a connecting rod assembly is not used.
The invention has therefore the objective to design a facility for needling of fleece of the above mentioned kind in such a way that an easy adjustment of the range of the motion component of the needle board in fleece feed direction is ensured even during driving of the needle board.
The objective of the invention is achieved by the feature that the swivel bearing of the rocker arm is seated on a rotatable crank arm and that, for adjustment of the rocking amplitude of the connecting pitman, the neutral rocking position of the rocker arm is adjustable via the crank arm between an end position essentially running in the direction of the connecting pitman and an end position running transverse thereto.
By displacing the swivel bearing of the rocker arm, which is kept stationary except for its displacement for adjustment of the rocking amplitude of the needle board in fleece feed direction, instead of the articulated bearing of the connecting rod at the rocker arm moving along with the rocker arm, very simple constructions features are achieved for adjustment of the rocking amplitude of the needle board in fleece feed direction. It is only necessary to displace the swivel bearing of the rocker arm via a rotatable crank arm. If the neutral rocking position of the rocker arm is essentially running in the direction of the connecting pitman, the length of lift of this rocking drive is determined by the cosine of the swivelling angle of the rocker arm as against its neutral rocking position. In a neutral rocking position of the rocker arm running transverse thereto, it is the sine of this swivelling angle that is relevant for the achievable rocking amplitude, so that, in terms of the motion component of the needle board in fleece feed direction, there is a lower limit value for the neutral rocking position of the rocker arm in the direction of the connecting pitman and an upper limit value for the neutral rocking position running transverse thereto. Thus, the swivel bearing of the rocker arm must be adjusted via the crank arm in such a way that the neutral rocking position of the rocker arm as desired in each case is achieved between the two end positions, with the shaft of the crank arm preferably provided in the motion area of the articulating axle between the rocker arm and the connecting pitman, to avoid a distinct displacement of the connecting pitman along with the displacement of the swivel bearing of the rocker arm. Though the connecting pitman may be effective outside the articulating axle between the rocker arm and the connecting rod at the rocker arm or at the connecting rod, particularly simple construction features are achieved in this context, when the connecting rod, the rocker arm and the connecting pitman are interlinked via a common articulating axle.
To adjust the rocking amplitude of the needle board in fleece feed direction, differently designed rotating drives for the crank arm may be provided. If, to this end, the crank arm is equipped with a toothed quadrant meshing with a driving pinion, favorable adjustment features are achieved permitting in a simple way an inifinite rotary adjustment of the crank arm via the shaft of the driving pinion.